Impregnating process.



UNITED STATES PATENT orruon.

RALPH w. n. moons, or wrrixmsnum, PENNSYLVANIA, Assrenon. To wnsrme HOUSE ELECTRIC AND MANUFACTURING COMPANY, A conroaATroN or marm- Patented Nov. 26, 1918.

SYLVANIA.

IMPREGNA'I'ING PROCESS.

1,286,051 Specification of Letters Patent. 110 Drawing. Application filed February 19, 1914. Serial No. 819,857.

To all whom it may concern Be it known that I, RALPH a citizen of the United States, and a resident of Wilkinsbur in the county of Allegheny and State 0 Tennsylvania, have invented a new and useful Improvement in .Impregnating Processes, of which the fol- In impregnating porous materials, such as paper and cloth, with waxy orresinous substances, it has heretofore been customary to take extreme precautions to guard against the presence of water during the impregnation. To this end, the materials to be im-- pregnated are usually baked for a considerable time and subjected to vacuum, the impregnating liquid being supplied while the vacuumis maintained.

I have discovered that, while water or other liquid is not desirable in the final product, its presence in the early stages .of the impregnation process may be highly beneficial, and may greatly expedite and im rove the process.

y invention has particular reference to an im roved process of impre ation in which I take advantage of the a ove mentioned discovery, and subject the material to be im regnated to a preliminary treatment wit water or other suitable moistening liquid. The water or other suitable liquid, hereinafter referred to as the moistening. 1i uid is vaporized in a'. subsequent stage of t e process, and the vapor so generated drives out the air present in'the mterstitial spaces of the fabric. In order to accomplish this result, the moistened fabric.

is treated with a suitable waxy, resinous or bituminous impregnating liquid, and heat is applied, to vaporize the moistening liquid and drive off the air and vapor, thus permitting the impregnating agent to enter all the poresof the fabric. Upon cooling, any trace of va may possib y remain in the fabric condenses, and the im re atin liquid takes its place. The exce mg y smal amount of water or other liquid that may be formed by this condensation is not suilicient to wet the final W. E. Moons, V

r of the moistening liquid that I will illustrate my process by reference to the impregnation of paper or cloth with waxy bodies, such as ceresin, and a prelimi nary treatment with water. I first moisten the paper or cloth with water, either by dipping or sprinkling. The fabric need not be thoroughly saturated, since only enough water is required to supply sufiicient aqueous vapor to ex el all thd air from the fabric. I then sub ect the fabric, by immersion or otherwise, to the liquefied wax, and heat until the temperature of the treated fabric is raised to a pointconsidera'bly above the boiling oint of water. A temperature of 160 or 175 C. is not excessive. I continue the heating until'bubbling has ceased for some time, in order to insure the complete expulsion of the air and the water, and I then reduce the temperature nearly to the solidifying point of the Wax and remove the fibrous material from the bath.

If, as is frequently the case, I desire to use an impregnating material at a temperature above t e boiling oint of water as when the melting point 0 the impregnating material is above 100 0., I prefer to carry out my process under sufiicienti induced pressure'to raise the boiling point of the water above the initial temperature of the melted wax or other impregnating material at the beginning of the treatment. Pressure may also be applied, if desired, after the ir'nfpregnatin step, and rvhile the treated abrlc is coo ing.

The example which I have 'ven and in. which water and wax are t e materials used, is to be understood as merely illustrative and not as limiting my invention, which complrehends broadly the use of any liquid as t e moistening agent which does not readily dissolve the impregnating ageiit and the boiling point of which is either above the melting point of the impregnating agent orv can be raised above such melting point by the application of fpressure. In my proe- I etc., and I may appl my process to every variety of porous su stance,.such as cloth, paper, wood, or even closel wound coils of wire or assembled con enser sections having dielectric layers of fabric.

I claim as my invention:

1. The process of impregnating porous material which com rises moistening the material with a liquid having a relatigely low boiling point and causing the replacement of the moistenin liquid, by the application of heat, with an impregnating liquid insoluble in the said moistening liquid Y and of higher boilin point.

2. The process 0 impregnating porous material which comprises moistening the material with a liquid of relatively low boiling point, treating the moistened material under super-atmospheric pressure with an impregnating liquid insoluble in the said moistening liquid and of hi her boiling point, and heating to about the oiling point of the moistening li uid.

3. The process 0 impregnating porous material which comprises moistening the material with a liquid havin a boiling point which is normally relative y' low, treating the moistened material with an impregnating liquid under a pressure such that the moistening liquid cannot boil, although the temperature of the impregnating liquid at the beginning of the treatment is above the boiling pointof the moistening liquid, and heating to a temperature at least high enou h to cause boilingmf. the moisteninlg liqui and until bubbling, due to such boi ing, ceases. v I

4. The process of impregnating porousmaterial which comprises moistenin the material with water, immersing the moistening material in a melted waxy1 substance that is insoluble in water, and' eating the said waxy substance above 100 C.

In testimony whereof, I have hereunto subscribed my name this 16th day of Feb.

RALPH W. E. MOORE. Witnesses:

Gonnm E. McGEn, B. B. Hmns.

It is hereby certifietl that in Letters Patent No. 1,286,057, granted November he application of Ralph W. E. Moore, of Wilkineburg, Pennsyl- ,"'an error appears in the 2s, vaniafior an improvement in Impregneting Pr printed specification requiring correction as follows: Page 2, line 22, claim 2, for the v vord about reed qbove; en d that the said Lettete Patent should. be mad with this correction therein that the eeme may conform to the record of the ease in the Patent Office.

'Signed and sealed this 24th day ofDecember, A. 11,1918.

' F. w. H. CLAY,

Acting GmmiuiowpfPatenta. 

